In general a fitler centrifuge or centrifugal filter comprises a rotary basket or drum which may be driven at high speeds centrifugally to cast a suspension of particulate material in a liquid phase against a filter medium, e.g. filter cloth lining the drum. The centrifugal force drives the liquid phase through the filter medium on which the solid phase is retained in a filter cake.
It has been proposed to increase the throughput of such filters by hydrodynamically increasing the pressure differential acrsoss the filter medium, e.g. by evacuating liquid from the far side thereof and/or applying a fluid pressure to the downstream side thereof with respect to the direction of flow of the liquid through the filter medium. A system which evacuates the space around the upstream side of the drum is limited in the pressure differential which can be applied by the vapor pressure of the liquid phase.